Portable electronic devices such as laptop PCs, tablet PCs, digital cameras, mobile phones, portable gaming devices, earphone-type music players, RF headsets, hearing aids, recorders, which are portable while being used by the user are rapidly increasing in recent years. Many of these portable electronic devices have therein a rechargeable battery, which requires periodical charging. To facilitate the work for charging the rechargeable battery mounted in an electronic device, there are an increasing number of devices for charging rechargeable batteries by using a power-supplying technology (wireless power transmission technology performing power transmission by varying the magnetic field) that performs wireless power transmission between a power-supplying module mounted in a charger and a power-receiving module mounted in an electronic device.
As a wireless power transmission technology, there have been known, for example, a wireless power transmission technology that performs power transmission by means of resonance phenomenon (magnetic field resonant state) between resonators (coils) provided to the power-supplying module and the power-receiving module (e.g. see PTL 1).
Further, according to the above-described wireless power transmission technology, a magnetic field is generated in the vicinity of the resonators of the power-supplying module and the power-receiving module, while a resonance phenomenon takes place between the resonators. Consequently, an Eddy Current occurs due to the magnetic field, thus generating heat in a stabilizer circuit, a charging circuit, a rechargeable battery, and other electronic components provided nearby the power-supplying module and the power-receiving module, which may cause with the result that an adverse effect may occur in the rectifier, and the stabilizer circuit, the charging circuit, the rechargeable battery, and the other electronic components may be adversely affected.
To address this issue of magnetic field, for example, PTL 2 discloses a power transmission system that is said to allow reduction of leak electromagnetic field in a power-supplying device configured to transmit power by means of contactless power transmission. Further, PTL 3 discloses a power transmission/reception device said to be capable of reducing magnetic field between a power-transmitting coil and a power-receiving coil.